Geology Reference
In-Depth Information
Birth
The Formation of Earth
Spanning the billions of years before Earth's formation
In the beginning, there was no Earth, or any Sun to warm it. Our Solar System, with its
glowing central star and varied planets and moons, is a relative newcomer to the cosmos—a
mere 4.567 billion years old. A lot had to happen before our world could emerge from the
void.
Thestagewassetforourplanet'sbirthmuch,muchearlier,attheoriginofallthings—the
Big Bang—about 13.7 billion years ago, by the latest estimates. That moment of creation
remains the most elusive, incomprehensible, defining event in the history of the universe.
It was a singularity—a transformation from nothing to something that remains beyond the
purview of modern science or the logic of mathematics. If you would search for signs of a
creator god in the cosmos, the Big Bang is the place to start.
In the beginning, all space and energy and matter came into existence from an unknow-
able void. Nothing. Then something. The concept is beyond our ability to craft metaphors.
Our universe did not suddenly appear where there was only vacuum before, for before
the Big Bang there was no volume and no time. Our concept of nothing implies empti-
ness—before the Big Bang there was nothing to be empty in.
Then in an instant, there was not just something, but everything that would ever be, all at
once.Ouruniverseassumedavolumesmallerthananatom'snucleus.Thatultracompressed
cosmosbeganaspurehomogeneousenergy,withnoparticlestospoiltheperfectuniformity.
Swiftly the universe expanded, though not into space or anything else outside it (there is no
outside
toouruniverse).Volumeitself, still intheformofhotenergy,emergedandgrew.As
existence expanded, it cooled. The first subatomic particles appeared a fraction of a second
after the Big Bang—electrons and quarks, the unseen essence of all the solids, liquids, and
gases of our world, materialized from pure energy. Soon thereafter, still within the first frac-
tionofthefirstcosmicsecond,quarkscombinedinpairsandtripletstoformlargerparticles,
including the protons and neutrons that populate every atomic nucleus. Things were still ri-
diculously hot and remained so for about a half-million years, until the ongoing expansion
eventually cooled the cosmos to a few thousand degrees—sufficiently cold for electrons to
latch on to nuclei and form the first atoms. The overwhelming majority of those first atoms
